Mold and AC

Greetings, all. As summer approaches, I am considering what to do for air conditioning in my new (to me) house. Retrofitting it for central air is not a possibility, even though I know when done right that can be best for folks with mold issues. My neighborhood has high amounts of outdoor molds (ugh) so opening the windows and using fans is not an option, either. I am choosing between ductless mini-splits and window AC units. Hoping for advice from others who have made these decisions with mold in mind.

Everyone I know with mini-splits loves them dearly, and everyone dislikes window AC units, so I'm not wondering which is a better AC system. That's obvious. ;) I'm curious if one is especially better or worse in terms of mold growth, mold reproduction, or mold from outdoors being introduced into an interior space.

I planned to get mini-splits this spring, but financial issues (partner's job is safe for now, but who knows about a year from now, so we want to maintain our savings as much as possible) and COVID-19 (I don't want people in my house to install mini-splits) have complicated the plan.

If you have advice for the least mold-dangerous way to have window units, then let me know. Ditto for brands or types of window units.

(And more off-topic, if you have installed mini-splits yourself, then tell me how easy or difficult that was!).

Thank you!

saraeli, sorry I don't have much practical knowledge of A/C units, or central air vs wall unit or mini-splits...but I have a similar concern about mold as an ongoing problem or well another expensive nightmare. I was cleaning my bedroom and happened to shine a bright light up into the A/C vent. I saw clumps of grey, I think it might be insulation, confusing because it is also grey, with flecks of black and dust, but I'm going to stick a vacuum cleaner attachment in there and see if I can remove the dust in there. Anyone know if this is a good idea? Will it just stir up toxic dust spores? I sent a mold testing kit and it supposedly came back clean, even though I still see black-mold (mildew?) on the drywall and ceiling in the bathroom especially, as during a cheap remodel they removed the hot-lamp light and bathroom-fan that I think was keeping it in check before...I've been going through my room cleaning out the dust, and making sure everything is wiped down with either soap and water or isopropyl alcohol, anyway for me it makes a difference! Even a reasonably decent tower fan (I have 2 tower fans always running in my room) with some type of filter creates pleasant white noise and keeps air circulating like an air-bath, though not sure how effective filters (they have MERV-ratings) or UV-light had been proven to be. As for A/C units, I always wondered how the portable units work, like if they always need an evaporation tube to the outside or what, especially in humid climates.

Another reason to get a window a/c unit as it gives you a really good idea of what size mini split you would need. If you buy a window unit thats 8000 BTU and it works really well cooling your place. When a contractor comes in and says you need a 12000 BTU mini split you can say you dont need you that big and were happy with the window unit that was only 8000 BTU and size it knowing that. It will save money and your comfort level will be much better.

Mini splits are air source heat pumps.

I have not installed one personally but most require special tooling ( vacuum pump) some places its actually illegal unless your a licensed HVAC person to turn the refrigerate valve on. That said you could do 90% of the work yourself and hire a HVAC contractor to do the last 10%. Or hope the HVAC police don't show up at your house. The more expensive units usually void the warranty if you install yourself.

YouTube has lots of videos on the installs.

I remember reading/hearing mold sources recommending ductless mini-splits as a better option for cooling in refards to mold, although they can get mold, too, but without the ducts there’s less to deal with. I don’t know much about them.

We replaced our central AC and ductwork with a new one and got all hard pipe ducts. We had an air purifier and dehumidifier installed the ductwork.